Singapore has joined the global race to reach net-zero emissions to avoid the harshest impacts of climate change, and is looking to reduce its reliance on fossil fuels by exploring other low-carbon alternatives.
Two studies had earlier been commissioned to look into two options, and the authorities on Wednesday (June 23) gave an update on their findings and the next steps forward for the country.
The studies had looked at the feasibility of using hydrogen as a fuel as well as the potential for deploying carbon capture, utilisation and storage (CCUS) technologies in Singapore.
Hydrogen is considered a cleaner fuel as it produces no planet-warming carbon dioxide (CO2) when burned, while CCUS gives the option of capturing CO2 emitted from factories and either storing the gas underground or converting it to other useful substances - preventing it from reaching the atmosphere.
"The studies highlighted the pathways for low-carbon hydrogen and CCUS that could be relevant for Singapore, and the barriers to deployment that would need to be overcome," said five agencies in a statement.
The five are the National Climate Change Secretariat (NCCS), the Economic Development Board (EDB), the Energy Market Authority (EMA), the Maritime and Port Authority (MPA) and the Civil Aviation Authority of Singapore (CAAS).
These emerging technologies are crucial for helping Singapore decarbonise, as the Republic has little other option to cut its carbon footprint.
Added the authorities in the joint statement: "As an alternative energy disadvantaged country, we expect these technologies to play important roles in our transition to a low-carbon future."
The ability to harness the sun's energy, for instance, is limited in a highly built-up, small country that lacks land for large solar farms. Rooftop solar panels could also be shaded by other buildings.
CO2, released when humans burn fossil fuels and cut down forests, is the main gas driving global warming.
Scientists have warned that by 2050, the world needs to reach net-zero emissions - meaning reducing emissions as much as possible and sucking up any remaining CO2 through efforts such as CCUS and reforestation - to avoid the harshest impacts of climate change.
Currently, more than 95 per cent of Singapore's energy is generated from natural gas. This is the cleanest form of fossil fuel, but it is still a fossil fuel nonetheless.
Hydrogen is abundant in the environment, but it exists in other forms, such as water (H2O) and methane (CH4).
For it to be considered a green fuel, hydrogen has to be generated in a way that also produces zero emissions.
For example, hydrogen gas can be extracted through a chemical process known as electrolysis, which involves running an electrical current through water to split the water molecule into its component elements.
But if the electricity required for electrolysis comes from fossil fuel-generated sources, it may not be considered green.
The feasibility study had concluded that given Singapore's limited renewable energy resources, it is challenging for Singapore to produce green hydrogen at scale using domestic green electricity.
"(Thus), Singapore would need to explore various supply pathways for price-competitive low-carbon hydrogen," said the statement.
To this end, the NCCS, EDB and EMA are studying whether hydrogen can be imported via ships or pipes, or whether hydrogen can be produced in a low-carbon way domestically.
This includes, for instance, conducting the electrolysis of water using imported renewable energy, or by pairing CCUS technologies with steam methane reforming. This is a common method of producing hydrogen but is not considered that green as the process still releases CO2.
The study also found that other technical and economic challenges could hinder widespread hydrogen use, including the need for extensive infrastructural support for the transport, storage and use of the gas.
Various sectors in Singapore will take further steps to see how hydrogen can be used in the various industries, said the agencies.
MPA, for instance, has announced a centre to focus Singapore's efforts in maritime decarbonisation.
Hydrogen could be an alternative for ocean-going vessels as it can be used as a fuel. The maritime sector is a huge source of emissions, and replacing marine fuel with hydrogen could help this sector decarbonise.
The other study on CCUS technologies had found other obstacles that need to be overcome for them to be used in Singapore.
For instance, in terms of carbon capture, the majority of carbon dioxide emissions from industrial and power plant facilities are dilute, at between 3 per cent and 15 per cent.
Such low concentrations of CO2 in emissions make it expensive and challenging to capture CO2 for subsequent conversion or storage.
Gases usually move from areas of high concentration to areas of low concentration through diffusion. So low-concentration levels would mean a lot of energy is required to separate or capture the gas for other applications.
Carbon storage is also usually done underground, but Singapore does not have any known suitable geological formations for the permanent storage of CO2 underground, the study found.
Utilising captured carbon for other uses - such as concrete or kerosene - is also more expensive and energy-intensive than conventional processes.
The next steps for Singapore are to study new chemical processes that could make utilising captured carbon more effectively, and work with partners to overcome the other barriers, said the authorities.
"Singapore will continue to invest in research to develop innovative solutions to overcome these barriers and reduce the costs of CCUS," said the agencies.
"Singapore will also seek partnerships on opportunities to pilot and test bed new CCUS solutions which have the potential to scale in the long run."